THE MIG1 REPRESSOR FROM KLUYVEROMYCES-LACTIS - CLONING, SEQUENCING AND FUNCTIONAL-ANALYSIS IN SACCHAROMYCES-CEREVISIAE

Sequence comparisons between Saccharomyces cerevisiae ScMig1 and Asper gillus nidulans CREA proteins allowed us to design two sets of degener ate primers from the conserved zinc finger loops. PCR amplification on Kluyveromyces marxianus and K. lactis genomic DNA yielded single prod ucts with sequences closely related to each other and to the correspon ding regions of ScMig1 and CREA. The KIMIG1 gene of K. lactis was clon ed from a genomic library using the K. marxianus PCR fragment as probe , KIMIG1 encodes a 474-amino acid protein 55% similar to ScMig1. Besid es their highly conserved zinc fingers, the two proteins display short conserved motifs of possible significance in glucose repression. Hete rologous complementation of a mig1 mutant of S, cerevisiae by the K. l actis gene demonstrates that the function of the Mig1 protein is conse rved in these two distantly related yeasts.